The New Jersey Republican-machine-backed candidate in an open-seat primary led a prominent tea party candidate by 11 points in a Monmouth University Poll released Thursday.

In the race to replace retiring Republican Rep. Jon Runyan, former Randolph Mayor Tom MacArthur, who is backed by the county establishments of New Jersey's 3rd District, had the support of 46 percent of likely primary voters, while 35 percent backed tea party favorite and ex-Bogota Mayor Steve Lonegan, the party's nominee in last year's Senate special election. Twenty percent of those surveyed were undecided.

The outcome of the June 3 primary is highly consequential to the general. Most New Jersey and national Republican operatives are aiming for a MacArthur victory, fearing that a tea party candidate could lose the seat to Democrats. The Democratic candidate, Burlington County Freeholder Aimee Belgard, is a safe bet to win her party's nomination, and at this point the race is rated a Tossup by the Rothenberg Political Report/Roll Call. The survey was conducted May 12-14 among 505 likely voters drawn from a list of registered Republican voters who cast ballots in at least one of the past four regular primary elections. The sample was further screened for those who report being either "certain” or "likely" to vote in June. The poll included 472 live interviews over land lines and 33 via cellphone. The margin of error was 4.4 points.

Forty-two percent of respondents said they had a favorable view of MacArthur, while 14 percent viewed him unfavorably. Lonegan, the party nominee against now-Democratic Sen. Cory Booker in the 2013 special, was more well known than MacArthur. Thirty-nine percent of those surveyed said they had a favorable view of Lonegan, while 24 percent had an unfavorable perception.

MacArthur is largely self-funding his campaign. As of his first quarter fundraising report , he had put $2 million into his campaign, dwarfing Lonegan's war chest.

Runyan and the U.S. Chamber of Commerce endorsed MacArthur earlier this week. But MacArthur earned the most consequential primary endorsements earlier this year — both of the local Republican parties in the district's two dominating counties backed him, meaning he will have a preferential ballot placement.